Synthesis and degradability of copolyesters of 2, 5-furandicarboxylic acid, lactic acid, and ethylene glycol
2015
Wu, Hongli | Wen, Binbin | Zhou, Hua | Zhou, Jiadong | Yu, Zuolong | Cui, Liyan | Huang, Ting | Cao, Fei
Polyethylene 2, 5-furandicarboxylate-lactic acid copolyesters (PEFL) were synthesized from bis (hydroxyethyl)-2, 5-furandicarboxylate and oligomer of l-lactic acid, through two-stage condensation. The polyesters were characterized using FTIR, ¹H NMR, GPC, and WXRD. The weight-average molecular weight (Mw) of the polyesters ranged from 68240 to 130433. The glass transition temperature (Tg) of the copolyesters increased gradually with increasing content of 2, 5-furandicarboxylate. In phosphate buffer solution (PBS, pH = 7.4) and in soil, the degradability of the polyesters was evaluated for 55 d. More weight loss was obtained with a higher ratio of lactate polymers in soil than those with a lower ratio in PBS. After 55 d, the weight loss of PEFL20/80 reached 65% and 24% in soil and PBS, respectively. However, the mole fraction of lactyl and furanic units that was calculated by ¹H NMR data did not change. Comparing the scanning electron microscopy images, we found many micro-cracks on the copolyester surfaces. Meanwhile, Mw and Tg also decreased prominently during degradation.
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